This invention relates to a sash drive assembly for sliding sashes.
Sashes of the sliding type are often heavy or sticking and are often tightly held by sealing tracks so that especially weak or infirm persons need means for operating them.
The invention is a self-contained drive assembly for sliding sash windows. It comprises a rack gear adapted to be connected to the sash parallel to the direction of sash movement and a drive unit adapted to be mounted on a widow frame element associated with a sash and extending in the same direction. The drive unit comprises a housing containing a drive motor and output spur. It also comprises an L-shaped engagement lever pivotally attached to the housing at its vertex and a rack guide pivotally attached to the L-shaped engagement lever on the short arm of the xe2x80x9cLxe2x80x9d. By manipulating the long arm of the L-shaped lever, the user can move the guide to position the rack against the spur gear in a firm but releasable way so that when the motor in the housing is activated, the spur drives the rack and, hence the sash, up or down. Batteries for the motor and controls may be provided in the housing.